The overwhelming majority of vehicles use Otto-cycle (throttled, spark-ignited) engines. Such engines may be fueled by gasoline, natural gas, liquefied petroleum gas (LPG), alcohol, or propane. In the U.S. over 175 Million vehicles use Otto cycle engines.
Otto-cycle engines control engine air consumption with a throttle. Air flows past the throttle, through the intake manifold, and on to the cylinder head. The manifold has four primary purposes, as noted below:
1. to maximize flow into the engine PA0 2. to equally distribute up to five fluids to each cylinder PA0 3. to provide adequate air/fuel mixing PA0 4. to add enough heat to vaporize the fuel. PA0 good distribution PA0 stable flow PA0 effective tuning PA0 equal heating of all runners. PA0 a plenum, PA0 an aperture in the plenum through which the plenum can receive a gaseous fuel mixture, PA0 first and second branch openings into the plenum, the openings being disposed in substantial opposition to each other across the plenum, PA0 first and second branch conduits communicating with said first and second branch openings respectively, PA0 each branch conduit divaricating into a plurality of runner conduits all of which terminate at their connections to a head flange; the various gaseous paths, each defined by one of the branch conduits and one of the runner conduits into which the branch conduit divaricates, being substantially free of abrupt angulations; and all said paths having substantially the same length beginning at the plenum, substantially the same volume, and substantially the same radius and arc-length of curvature. PA0 receiving the mixture in a plenum through an aperture, PA0 passing the mixture out of the plenum through first and second branch openings disposed in substantial opposition to each other across the plenum, PA0 passing the mixture into first and second branch conduits communicating with said first and second branch openings respectively, each branch conduit divaricating into a plurality of runner conduits all of which terminate at their connections to the engine; and PA0 ensuring that the various gaseous paths, each defined by one of the branch conduits and one of the runner conduits into which the branch conduit divaricates, all have substantially the same length beginning at the plenum, substantially the same volume, and substantially the same radius and arc-length of curvature.
intake air PA1 idle by-pass air PA1 fuel PA1 Positive Crankcase Ventilation (PCV) gases PA1 Exhaust Gas Recirculation (EGR) gases
While OTTO-cycle engines have been developed and improved over many years, there remains room for improvement, particularly in connection with the distribution of fuel to the cylinders and with the improvement of fuel-flow contour.